Without prediction the partition has been suddenly damaged for some cause and you cannot access it. In order to use it again, you usually need to format it.
But we all know that the formatting operation will remove all data stored in it. Therefore, we would need to recover them from the damaged partition on Mac with third-party Mac data recovery software before doing so.
Here you could try EaseUS Data Recovery Wizard for Mac which is specially designed to recover Mac files lost due to virus attack, formatting, deletion or partition loss, even if you have formatted your damaged Mac partition.
Important Notes for Successful Data Recovery
Whether you can recover lost data successfully or not depends largely on what you have done. Immediate action should be taken to avoid further damage to the location of data loss. This means don’t try to write any new data into it, otherwise you could overwrite the lost original data.
EaseUS is a company specializing in data security, have developed products for data recovery, data backup and disk management, and so on.
EaseUS Data Recovery Wizard for Mac is one of them dedicated to recovering data lost under Mac OS X, compatible with Mac OS Sierra, Mac OS X 10.11/10.10/10.9/10.8/10.7/10.6. The following will have a guide to help you recover the damaged partition on Mac with this software.
Guide to Recovering Data from Damaged Partition on Mac with EaseUS Data Recovery Wizard
Step 1: Install and run EaseUS Data Recovery Wizard for Mac on your Mac, select the partition where you lost your data, and then click Scan.
Step 2: This software will perform a scan on the selected partition to look for lost data, the time it takes depends on the amount of your data in it.
During the scanning process you can suspend and then continue scanning, and also preview the found files and recover them according to your own needs.
Step 3: All files found will be displayed in the left pane, listed by path and type.
It allows you to preview them before recovering them, finally check those you want and click on Recover, it is better to save the recovered data on an external storage device to avoid data overwriting.